Vehicles and other structures use closure systems to automatically open and close closure members. Closure members of vehicles include, but are not limited to, lift gates, trunks, sunroofs, windows, doors, and other devices. The speeds at which the closure systems operate are generally at speeds that will result in minimal injury or damage to persons or objects if contacted by the moving closure member. While closure systems operate to automatically and safely open and close closure members, decreasing closure system cycle time while maintaining safe pinch forces is generally a goal as operators and users of vehicles, for example, tend to want fast operation. However, typical closure members are large in mass and, as a result of this large mass, it is important to maintain velocity of the closure members at a rate that will not produce excessive pinch force in the event of a collision with an obstacle, such as a person or object.
Conventional closure systems generally utilize obstacle detection for detecting when an obstacle is blocking a closure member from opening and closing. Because closure systems generally rely on contact sensing for detecting a collision with an obstacle, closure systems generally have a conventional maximum speed for opening and closing the closure member. For example, a conventional closure speed for a lift gate is approximately 200 millimeters per second. In other words, the closure system is operated slowly enough to ensure that pinch forces remain low enough to be safe to obstacles that are contacted by a moving closure member and the closure systems. Although the speeds are relatively slow, collision with an obstacle at these speeds can place significant strain on the closure system in reacting to a collision with the obstacle.
One technique for preventing a closure member from contacting an obstacle includes the use of a non-contact sensor that senses when an obstacle is in the path of a closure member. If the closure member is moving (i.e., being opened or closed), and the non-contact sensor senses that an obstacle is in the path of the moving closure member, then the closure member is stopped from moving or reversed in direction of movement. While the functions of stopping or reversing a closure member are practical in terms of preventing an obstacle from becoming injured or damaged, it is impractical for many everyday situations. For example, children quickly jumping into backseats, adults putting final groceries in the rear of the vehicles, or people moving objects into the path of closure members while the closure members are moving cause the closure systems to inconveniently stop or reverse direction. Once the closure member has stopped or reversed direction, a user controlling operation of the closure member must reinitiate the process for opening or closing the closure member. What is needed is a mechanism for increasing higher cycle rates while maintaining safety of operation of closure systems.